Interpretive Summary: The structure of D-glucaric acid, a diacid derivative of glucose that is useful for generating amide-based polymers, was studied by NMR spectroscopy, X-ray crystallography, and computation chemistry methods. In general, the methods produced a picture of a molecule that prefers a “bent” conformation that does not have potentially 1,3 oxygen-oxygen interactions. The X-ray and lowest-energy modeling structures were in good agreement but with NMR data in solution yielded a somewhat different “average” conformation. The data should be of interest to researchers working to understand the properties of polymeric materials formed from D-glucaric acid.

Technical Abstract:
D-glucaric acid was characterized in solution by comparing NMR spectra from the isotopically unlabeled molecule with those from D-glucaric acid labeled with deuterium or carbon-13 atoms. The NMR studies provided unequivocal assignments for all carbon atoms and non-hydroxyl protons of the molecule. The crystal structure of D-glucaric acid was obtained by x-ray diffraction techniques and the structure was a close match to the low energy conformation generated from a Monte-Carlo-based searching protocol employing the MM3 molecular mechanics program. The molecule adopts a bent structure in both the crystalline and computationally generated lowest-energy structure, a conformation that is devoid of destabilizing eclipsed 1,3-hydroxyl interactions.